Methodology for neutron spectrum measurement independent of position and direction of neutrons incident on detector

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K18303
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 80040:Quantum beam science-related
• Research Institution: Hiroshima University
• Principal Investigator: Kajimoto Tsuyoshi 広島大学, 先進理工系科学研究科(工), 助教 (70633759)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 中性子場 / 放射線遮蔽 / 高エネルギー加速器 / 有機液体シンチレータ / アンフォールディング法

Outline of Final Research Achievements

Methodology for measuring neutron energy spectrum by using organic liquid scintillator and unfolding derivation method was proposed in the neutron field with unclear positional and directional distributions. The difference of neutron response by the position and direction incident on the scintillator was verified from an experiment and simulations. By dividing the neutron responses by the length between entering and outgoing positions in the scintillator, the difference could not be eliminated, however, became negligibly smaller to uncertainty of the unfolding method. An experiment to measure neutron energy spectrum by applying this methodology was performed in a high energy accelerator facility.

Free Research Field

放射線計測

Academic Significance and Societal Importance of the Research Achievements

中性子の位置分布および方向分布が不明な場所で中性子エネルギースペクトルが測定できる手法を確立した．これにより，これまで測定が困難であった場所でのエネルギースペクトル測定が可能となる．そこで，高エネルギー加速器施設で実験を行い，手法を適用することでエネルギースペクトルを導出した．中性子の多い場所から少ない場所の複数点で測定し，これまで得られていた中性子の減弱データだけでなく，エネルギースペクトルの変化を観測できた．スペクトルの変化は効果的な中性子遮蔽設計をする上で重要な情報となる．